Automatic regulating device for air heating plants in railway vehicles



y 1940- F. vo'N scHUTz ET AL 2.199.531

AUTOMATIC REGULATING DEVICE FOR AIR HEATING PLANTS IN RAILWAY VEHICLES Filed Spt. 25, 1936 4 Sheets-Sheet 1 Fig.1

mn /Jogzzawifgklf M -JM M May 7, 1940,

F. VON SCHUTZ ET AL AUTOMATIC REGULATING DEVICE FOR AIR HEATING PLANTS IN RAILWAY VEHICLES Filed Sept, 23, 1936 4 Sheets-Sheet 2 a g Int/e 96???- 2W8,

y 7. 1940. F. VON SCHUTZ Er AL 2.199.531

AUTOMATIC REGULATING DEVICE FORAIR HEATING PLANTS IN RAILWAY VEHICLES Filed Sept; 23; 1936 4 Sheets-Sheet s gal/e172 27.2

' y 1940. F. VON SCHUTZ El AL I 2.199.531

AUTOMATIC REGULATING DEVICE FUR AIR HEATING PLANTS IN RAILWAY VEHICLES Filed Sept. 23, 1936 4 Sheets-Sheet 4 Fig.6

5- 42 Inventor":

Zatented May 7, 1940 AUTOMATIC REGULATING DEVICE FOR AIR gATIgG PLANTS IN RAILWAY VE- Friedrich von Schlitz, Bcrlin-Iichterielde-West,, and Bruno Voge, Berlin-Wilhelmshagen, Germany, assignors to Julius Pint'sch Kommanditgesellschai't, Berlin, Germany Application Sebtember 23, 1936, Serial No. 102,194 In Germany October 4, 1935 I 15 Claims.

This invention relates to a device for auto- 4 matically regulating air heating in railroad cars,

in which the fresh air prior to entering the car is treated in a heater operated by a heating medium, such as steam, warm water, gases of combustion, or waste gases. 4

The invention in some respects constitutes an improvement of the regulating device described and claimed in my co-pending application Ser.

No. 52,738, filed December 3, 1935, now Patent In the device according to this former application the supply of heating medium to the air heater is controlled by an inlet valve adjusted 5 by a thermal relay the heating element of which is switched on and thereby causes the closing of the inlet valve if the desired room temperature is exceeded in a certain number of compartments of the car. This is efiected by means of a maxigo mum current relay connected in the circuit of the heating element and having its exciting winding traversed by the sum total of the currents switched on by contact makers arranged in the compartments.

u The present invention aims at improving this regulating device, in which the inlet valve for the heating medium is throttled if the room temperature is exceeded in a certain number, say, seven of nine, compartments of a car, and gradually go completely closed ii. the impulse given continues long enough, which is usually the case owing to the lagging of the change inroom temperature relative to regulation. It is, however, preferable to provide for regulation in such manner that the supply of heating medium, instead of being fully shut oif, is throttled to a varying extent, de-

pending on the number of compartments in which room temperature has been reached. In this way, smoother regulation is insured and over-control w avoided. i

For this purpose, according to the present invention, the thermal relay actuating the valve for the heating medium is not heated elec rically, as

in.the device according to the precedingapplica- 5 tion, but by means of the heating medium for the air heater, this heating by the. heating medium being offset by cooling by means of an air current. Heating with the heating medium can be effected either by bringing the element of the 50 thermal relay that is sensitive to temperature into heat conducting connection with the inlet valve flown through by the heating medium or by having the element surrounded by a branch current of the heating medium. Theelement is 55 cooled by blowing an air current cooler than the heating medium against it, such as a branch current of the cold 'air supplied to the air heater or of the warm air coming out of the heater or a mixture of these two branch air currents. The degree of heating and cooling of the sensitive ele- 5 ment of the thermal relay and thus the temperature thereof and the position of the inlet valve for the heating medium controlled thereby are varied by changing the amount of-the'branch current of heating medium playing around the 10 elementor the quantity of the aircurrent blowing against it, variation being eiiected by the actuation of adjusting members in the branch piping of the heating medium or in the piping for blowing air, which are adjusted by contact makers sensitive to temperature and arranged in the compartments.

The use of warm airbranched ofli behind the air heater for blowing against the element sensitive to temperature afiords the advantage that the 0 temperature of this air varying with the lift of the valve for the heating medium influences that 01 the element in thesame direction and, with respect to regulation, has the effect and tendency to counteract all variations in the travel of the valve. l

By gradually throttling one of the branch currents or both of them it becomes possible in a device of this kind to adjust for instance the steam supply to the air heater at wfll. This gradual throttling in. a-car having compartments is effected according to the invention by means of a rotary magnet with the armature of which the adjusting member is coupled and whoseexciting windingv is flown through by the sum of the currents switched on by'the contact makers in the compartments.

According to the invention, the adjusting member or members in the branch conduits may also be actuated by an electrically heated thermal 40 relay the heating resistance or resistances of which i are individually or collectively flown through by the currents switched on by thelcontact makers in the compartments.

If the temperature of only oneheated room is 5 to be regulated a single contact maker controlling the heating of. the thermal relay will be suflicient.

In this instance, the adjusting member in the branch conduit actuated by the rotarymagnet or f the thermal relay may be replaced by'a magnetically actuated valve the excitation of which is switched on and off by a contact thermometer .in the heated room. To avoidtoo sudden actuation oi the valve'ior the-heating medium the jacket surrounding the evaporating vessel or the u magnet valve controlling a branching outlet fltted with throttling means may be provided, which is opened by means of a contact'thermometer arranged in the heated room and of a cut-out relay if the room temperature exceeds the contact temperature of this thermometer. The temperature of this thermometer is somewhat below that of the thermometer associated with the totally throttling magnet valve, so that during rising of the room temperature at first the air current acting upon the vessel of the thermal relay is reduced to the extent of this branch current and only completely shut off when the room temperature continues to rise further.

If heating of the element sensitive to temperature of the thermal relay is efifected by means of a current of the heating medium and not by heat conduction and if regulation is brought about by changing only the amount of the current of .blown air, provision is preferably made for preventing any variation in the amount .of the branch current of heating medium, apart from a single adjustment of a valve built into the conduit thereof, since a variation thereof would involve a change in the position of the valve for the heating medium, which, however, is exclusively to be caused by the setting of the adjusting member for the warm air branch current'efiected by the contact makers in the heated room.

For this purpose, the piping supplying heating medium to the air heater is provided behind the branching-off of the branch current of the'heating medium serving for acting upon the thermal relay with an in-built overpressure flap opening in the direction .of the stream of the heating medium and loaded by weight or spring in such manner that a certain pressure must prevail in the supply piping in front of this flap to cause opening of the latter. This arrangement prevents, even if the car requires very little heat and consequently very little heating medium or none at all-is supplied to the-air heater and the inlet valve is almost closed, that in the portion of the supply piping from which the partial current for the thermal relay is branched of! pressure drops below a certain limit and the quantity of this current decreases below a certain -point. I

When steam is used as heating medium for the air heater, the steam inlet valve can be throttled even if the steam is incompletely utilized in the air heater and steam flows out of the condensate outlet. For this purpose, a throttling station is provided in the condensate discharge pipe and in front thereof a conduit is branched oil! which leads into the jacket surrounding the evaporating vessel of the thermal relay. When steam instead of condensate comes out of the air heater, a portion thereof is forced by throttling to act upon the evaporating vessel of the thermal relay, whereby the steam inlet valve is throttled.

To avoid wide opening of the steam inlet valve in case of ,very great heat demand of the car and the admission of more steam than is condensed in the air heater, so that much steam comes out of the heater and, owing to the throttling of the steam at the outlet, damming up occurs whose effeet extends as far as the space directly behind the steam inlet valve, and, due to the resulting increase in pressure in the supply piping at the point where the branch current for the thermal relay is taken, to prevent any enlargement of the quantity of this current, the invention provides for the replacement of the throttling station in the condensate outlet by an overflow comprising a vessel into which the condensate discharge pipe opens below the level of the water of condensation. Owing to this arrangement, the overpressure of the steam in front of the overflow cannot be greater than the immersion of the pipe, which is kept so low that damming up of the steam at the point of withdrawal of the branch current does not occur.

By way of example, several embodiments of the invention are diagrammatically illustrated in the accompanying drawings, in which Figure 1 shows the regulating device of a steam-heated air heater, wherein the element sensitive to temperature of the thermal relay is heated by heat conduction from the steam inlet valve and is cooled by an air current blown against it, the amount of the current being changed by. an adjusting member actuated by a rotary magnet; Fig. 2, thethe thermal relay is heated by being acted upon by a branch steam current; Fig. 3, an adjusting member in the blower airpiping operated by means of a thermal relay; Fig. 4, an adjusting member constructed as magnet valve; Fig. 5, an adjusting member formed of two magnet valves; and Fig. 6, the regulating device shown in Fig. 2 equipped with an overpressure flap in the piping between the steam valve and the air heater and with an overflow vessel disposed on the conden sate outlet.

Referring to the drawings, the air heater i is supplied with heating steam by the conduit 2, and the condensate passes off through the piping 3.. In the live steam supply conduit 2 a steam inlet valve is provided the cone 4 of which is loaded by a spring 2| and connected with the movable bottom of the spring body 5 secured to the lid 38 of the valve box 31. Through a bore 38 in the lid 36, which serves also as guide for the pin 39 attached to the movable bottom of the spring body 5, the inside of the spring body 5-is in communication with the tubular evaporating vessel 1 provided with external ribs at the lower end and containing an evaporable liquid, such as ether.

The evaporating vessel I is made of material possessing good heat condpctivityand, owing to a heat-conducting connection of the'evaporati'ng vessel and of the lid 36 of the valve box 31, the

portion of the evaporating vessel 1 provided with cooling ribs issupplied by the piping 18 with air,

such as a branch current of the air coming out of the air heater, the amount of which can be varied by the adjusting member I9. The adjusting member l9, against the action of a return spring not shown, is adjusted by the rotary magnet 20 the exciting winding l2 of'which is connected in series with the contact thermometers I5 and the resistances l'l connected in parallel in the compartments of the car. In each compartment three contact thermometers I which make contact at different temperaures are ar- 7 ranged of which the one responding to the desired temperature is switched-on by a switch I 6.

- Into the jacket pipe 8 open below and opening into the drain funnel l I the condensate discharge pipe 3 is laterally introducedwhence a conduit 23 leads to the pipe -9, so that steam emerging from the air heater is takenup by the current of blowing air flowing through the nozzle 45 and conducted to the evaporating vessel 1.

iii

The action of the'device is as follows:

As soon as; heating steam flows through the valve, the evaporating vessel I being in heat conducting connection therewith will be heated,

so that the liquid contained therein evaporates,

the spring body 5 is extended owing to the increase in pressure produced and the valve cone 4 is brought closer to its seat and steam pressure is throttled. This heating by means of the heating steam is counteracted by the cooling effected-by the air current blowing against the evaporating vessel "I. Between heating of the vessel 1 by the heating steam and cooling by the current of blowing air a state of equilibrium is brought about, which by dimensioning "of the amount ofblowing air is 'so adjusted that the inlet valve at the resulting position of the cone:

4 permits the passage of an amount of steam required for heating the air to the desired temperature.

If the temperature in some compartments exceeds the desired degree, the therm pmeters I5 will make "contact therein and close the circuit of the exciting winding I2 by way of the resistances II. Since the latter are in parallel, the current flowing through the exciting winding I2will be the higher the more compartments have attained the desired room temperature. The rotary armature of the magnet 20 is drawn against the action of a return spring, not shown,

in the direction of the connecting line of the magnet poles and thereby so adjusts the throttle valve I9 coupled therewith that the amount of blowing air supplied .through the piping I8 is reduced. The temperature of the evaporating vessel I rises, as now heating bythe heating steam preponderates, and as a result thereof pressure in the vessel increases and throttles the steam'inlet valve 4 to a greater extent. Inversely, if the thermometers I open owing to lowering of the room temperature, the excita-- tion .of the rotary magnet will be reduced and the throttle valve I9 opened more fully. The

enlargement of the amount of "blower air re-,

duces again the temperature of the evaporating vessel I, so that the pressure therein decreases and the steam inlet valve is opened to a larger extent. In this way, automatic gradual regulation of the steam supply to the air heater in dependence upon room temperature is efiected.

If the temperature of the heating steam suppliedby the conduit 2 rises, the evaporating vessel I will be heated correspondingly more by heat conduction and throttling by the valve will increase. By suitable dimensioning of the device and the selection of the liquid contained in the evaporating vessel it is possible to cause variations in the state of the heating steam to be without influence upon the amount of heat supplied to the airheater per time unit.

To prevent the variable pressure of the in- -fiowing live steam from affecting the position of the valve, the valve cone is preferably relieved by arranging within the loading spring 2| a spring body 46 closed below whose inner space is in communication with the outer air and through .the conduit I4 whose bottom issuppo ted by the springplate 47 of the spring 2|". "The effective diameterrof diameter of the valvexseat, soth'at thesteam' pressure, acting on twosurfaces of equal size; can apply only two-equal and-oppositely directed forces to the movable portion of the valve, which ofl'set each other. a a v For cooling the evaporating vessel any medium, .such as' a branch current of the warm, air' coming out of the air heater or. a mixture of warm and cold air, may beused, provided;v that the-temperatureof the evaporatingvesseldue to blowing this medium againstit'is lower, than the temperature produced'by exclusive heating by heat conduction. Particularly suitable is the, employment of an air current having. outer temperature, for instance of a branch-current'of "the spring body lfi'isapproximately equal to the the fresh air supplied to the airheater, as then the outer temperature will be decisive also for the position of the steam inletvalve. A-plp ior supplying such a branch current of fresh air is shown*in Figure 1. The lower the'outer temperature themore preponderates cooling of the evaporating vessel .1 by the air. current .and

causesjwiderqopening' of the inlet -valve, where as, inverselyat high outer temperature the steam inlet-valve will be. increasingly throttled.

If excesssteam'flows through the condensate discharge pipe 3 from the air heater, which easi-- 'ly occurs particularly during heating up, it will be drawn up through the pipe 23 by the blower air current coming out of the'nozzle 45 and conducted to the evaporating vessel I which will be rapidly heated thereby and cause throttling of the steam inlet valve, so that losses due to incomplete-utilization of the steam in the air heater will be. avoided.

In the construction shown in Fig. 2 the thermal relay is heated by abranch current of the heating medium, which is branched off from the valve box 31 behind the valve seat and introduced by the conduit containing the valve 13 into the pipe 9 leading to the jacket 8 of the evaporating vessel I. The evaporating vessel'I is constructed as a coil closed below, which communicates with the spring body'5 through the conduit 6 and contains an easily evaporable liquid like ether.

From the jacket 8 a pipe 10 leads to the drain funnel I l for discharging the mixture of steam and air entering through the pipe' '9. In the condensate discharge piping 3 of the air heater I a throttling station 22 is provided and in front thereof a conduit 23 leading to the jacket 8 of the evaporating vessel I is branched off.

, The device functions in substantially the same manner as that shown. inFig. 1, though the evaporating vessel-'1 is heated not by heat con-,

duction'but by a branch steam current supplied If steam emerges from the condensate discharge piping .3 owing'to incomplete utilization 'of the heating steam in the airheater I, a portion thereof will'be forced by the throttling station 22 to flow through the conduit 23 to the to room temperature makes contact.

supply to an air heater is to be regulated which has to 'p'rovide several compartments with heat-' ina airJ- If, however, only one room is to be hehted', only a contact thermometer l exposed to -the-room temperature isarranged in the the double valve 21 by means of the bell crank 26-. The valve 21 at one end position shuts off the mixing'piping 9 and opens "the outlet 28, so that the air entering through the: conduit l8" the casing 29 surrounding the spring body passes into the atmosphere; when in its other-end position, the valve closes the outlet 28 and opens the mix-' ing piping 9 to cause air to flow through the piping 9 into which opens also the steam supply pipe l4 to the jacket 8 of the thermal relay controlling the steam inlet valve; Here, too, a

strong current flowing through the heating element l2 reduces the amount of blown air. and

thereby throttles the steam inlet valve 4 while a-weaker current or current failure increases --the amount of blown air and thus opens-the steam inlet valve 4. The provision of the thermal relay in the casing 29, i. e., in the air stream which owing to the outlet 28 is maintained even if the piping 9 is shut off, shortens the transit 30 time of the thermal relay if a branch current of the warm air coming out of the air heater.

serves as blowing air.

According to Fig 4 the adjusting member in the air conduit is constructed in the form of a magnet valve 30 in the exciting circuit of which the contact thermometer l5 disposed in the heated room is connected and which shuts off the air current when excited. To avoid too sud den closing of the steam inlet valve- 4 it is advis- 4o able to prolong in this construction the time for heating up or cooling the thermal relay 5, 6, 1, which may be done for instance by providing the jacket 8 with thick walls and insulating it.

. Soft regulation can also be efiected by provid- 45 ing in the air piping l8, besides the magnet valve 30, an outlet with a throttle 3| and controlled by a magnetic valve 32, as shown in Fig. 5. The exciting winding 33 of the valve 32 is cut out by a relay 34 when the thermometer 35 exposed The contact temperature of the thermometer 35 is slightly, e. g. 1, below that of the thermometer [5 arranged in the exciting circuit of the magnet valve 30. a

If the room temperature is below the contact temperature of the thermometer 35 and thus also below that of the thermometer [5, the valve 30 will be open and the valve 32 closed, so that the entire amount of air flowing through the 0 conduit l8 passes into the mixing pipe 9. If the temperature in the heated room rises, first the thermometer 35 will make contact and thus open the valve 32 through which a portion of the air flows outside, so that the jacket 8 will be sup- 5 plied with less air and the vessel 1 will be heated more. Should the room temperature still continue to rise, the thermometer l5 will also make contact and the valve 30 completely shut off the air current. The thermal relay 5, 6, I the evapo- 70 rating vessel of which is acted upon only by the steam flowing through the conduit I4 will therefore be increasingly heated and throttle the steam inlet valve still more.

In the construction shown in Fig. 6 the live 75 steam piping 2 leading to the air heater I is provided behind theinlet valve 4 and the branching of the conduit l4 with an overpressure flap 40 which opens in the direction of the flow of steam. The flap 40 is loaded by a weight in such manner that in the portion of the piping arranged in front thereof a certain minimum pressure must prevail which opens it. In the partition of the overpressure flap a small overflow opening 4| is provided. v

The condensate dischargepiping 3 opening into the draining funnel II is surrounded by an overflow vessel 42 the lateral overflow openings of which are so arranged that the piping 3 immerses to a certain extent in the condensate collecting in the vessel 42. At the bottom of the lattera narrow outlet opening 44 is provided for permitting outflow of the condensate when heating is stopped and thereby preventing freezing of the overflow,

These two devices function as follows:

The overpressure valve 40 prevents the pressure of the steam at the point of withdrawal of the branch current flowing through the conduit 14 and thus the amount of current from exceeding a certain minimum value at low heating output, so that the amount of this branch current remains practically unchanged even at low loading of the heating and regulation is not disturbed. Even when the car requires no heat, the steam inlet valve is not fully shut oil but always permits the passage of an amount of. steam suflicient to maintain the steam inlet valve in its heavily throttling position by acting on the evaporating-vessel I. This slight amount of steam protects the pipe 10 leading to the drain-- ing funnel ll against freezing. The small overflow opening 4| takes care that always some steam is supplied to the air heater I to prevent freezing thereof and especially of the condensate discharge pipe 3 which is particularly exposed to this danger. Owing to the arrangement of the overflow vessel 42 on the condensate discharge pipe 3, the pressure of the steam on leaving the heater cannotvexceed an amount fixed by the degree of immersion in the vessel 42. In this manner, the risk of an accumulation of pressure at the condensate outlet and of a reaction thereof with respect to the point of withdrawal of the branch current flowing through the conduit I4 is effectively eliminated, the amount of this branch current being upwardly limited by the same means.

By dimensioning the load of the overpressure flap 40, which may be varied by attaching weights or altering the setting of a loading spring, as well as by controlling the immersion of the overflow 42 at the condensate discharge one is therefore enabled upwardly or downwardly to limit changes in steam pressure at the point of withdrawal of thebranch current l4, due possibly to a very slight or very great heating output, in such manner that a variation of this branch current afiecting regulation does not occur.

We claim:

1. A device for automatically regulating the supply of heating medium to the air heater of an air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, combined with the spring. body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of heat to the vaporising vessel, a jacket surround- '(5 ing the vaporising vessel, a feed pipe for sup-' plying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, and means for auto-,

matically varying the cooling. of the vaporising vessel by the air in dependence upon the temperature of the car. 1

2. A device for automatically regulating the supply of heating medium to the air heater of an' air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, connected with the spring body and in heat-conducting connection with the heating medium valve, a vaporising liquid in the vaporising vessel, a jacket surrounding the vaporising vessel, a feed pipe for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, and means for automatically varying the cooling of the vaporising vessel by the air in dependence upon the temperature of the car.

3. A device for automatically regulating the supply of heating medium to the air heater of an air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, connected with the spring body, a vaporising liquid in the vaporising vessel, a jacket surrounding the vaporising vessel, a conduit branching off from the heating medium piping behind the valve for supplying a branch current of heating medium to thejacket, a piping for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, and means for automatically varying the cooling of the vaporising vessel by the air in dependence upon the temperature of the car.

4. A device for automatically regulating the supply of-heating medium to the air heater of an air-hea'ting plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relayior controlling the valve, said relay comprising in combination a spring body for actuating the valve, 2. vaporising vessel, combined with the spring body, a vaporising liquid in the vaporising ves-- sel, means for supplying a constant quantity of heat to the vaporising vessel, a jacket surrounding the vaporising vessel, a piping for conducting to the jacket a branch current of the heatingair emerging from the air heater, a discharge pipe extending from the jacket into the atmosphere, and means for automatically varying the cooling of the vaporising vessel by the air in dependence upon the temperature of the car.

5. A device for automatically regulating the supply of heating medium to the air heater of an air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, combined with the spring body, a vaporising liquid in the vaporising vessel, means. for supplying a constant quantity of heat to the vaporising vessel, a jacket surrounding the vaporising vessel, a piping for conducting to the jacket a branch current of the heating air supplied to the air heater, a discharge pipe extending from the jacket into the atmosphere, and means for automatically varying the cooling of the vaporising vessel by the air in dependence upon the temperature of ';he car.

6. A device for automatically regulating the supplyof heating medium to the air heater of an air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, combined with the spring body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of a heat to the vaporising vessel, a jacket surrounding the vaporising vessel, pipings for supplying to the jacket a branch current of the heating air emerging from the air heater and a branch current of the heating air supplied to the air heater, a discharge pipe extending from the jacket into the atmosphere, and means for automatically varying the cooling of the vaporising vessel by the air'in dependence upon the tem-. perature of the car. i

'7. A device for automatically regulating the supply of heating medium to the air heater of an air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, combined with the spring body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of heat to the vaporising vessel, a. jacket surrounding the vaporising vessel, a feed pipe for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, an adjusting member inthe air pipe extending to the jacket, and means for automatically controlling the adjusting member in dependence upon the temperature of the car. 7

8. A device for automatically regulating the supply of heating medium to the air heater of an air-heating plant for a railway car provided with compartments, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising a spring body for actuating the valve, a vaporising vessel, connected with the spring body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of heat to the vaporising vessell a jacket surrounding the vaporising vessel,

a feed pipe for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, an adjusting member in the piping supplying air to the jacket, a rotary magnet havinga rotary armature and an exciting winding, said rotary armature being operatively coupled with the ad- 1 justing member, and a contact thermometer and a resistance connected in series therewith in each of the compartments of the car, the said contact thermometers and resistances. in the compartments all being connected in parallel to one another and in series with the exciting winding of the rotary magnet.

9. A device for automatically regulating the supply of heating medium to the air heater of an air-heating plant for a railway car provided with compartments, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising a spring body for actuating the valve, a vaporising vessel, connected with the spring body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of heat to the vaporising vessel, a jacket surrounding the vaporising vessel, a feed pipe for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, an adjusting member in the piping supplying air to the jacket, comprising a casing provided with an outlet, a supply pipe and a discharge pipe for the air flowing through, a double valve for the alternate closing of the outlet and of the discharge pipe, a spring body, a vaporising liquid in said spring body and an electric heating element in said' spring. body, a contact thermometer and a resistance connected in series therewith in, each of the compartments of the car, said contact thermometer and resistance in the compartments all being connected in parallel with one another and in series with the electric heating element.

10. A device for automatically regulating the supply of heating medium to the air heater of an air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, combined with the spring body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of heat to the vaporising vessel, a jacket surrounding the vaporising vessel, a feed pipe for supplying a branch current of the heating air to the jacket, a discharge pipe. extending from the jacket into the atmosphere, an adjusting member in the pipe supplying air to the jacket, comprising a casing provided with an outlet, a supply pipe and a discharge pipe for the air flowing through, a double valve for the alternate closing of the outlet and of the discharge pipe, a spring body, a vaporising liquid in said spring body, an electric heating element in said spring-body, and a contact thermometer in the heated car, which is connected in series with the electric heating element. a

11. A device for automatically regulating the supply of heating medium to the air heater of an air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, .a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, combined with the spring body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of heat to the vaporising vessel, a jacket surrounding the vaporising vessel, a feed pipe 'for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, a magnetically controlled valve provided with an exciting winding in the piping supplying air to the jacket, and a contact thermometer in the heated car, which is connected in series with the exciting winding of the magnetically controlled valve.-

12. A device for automaticallyregulating the supply of heating medium to the air heater of an air-heating plant in a railway car, comprising a valve infthe piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for a tuating the valve,

with the exciting winding of the magnetically controlled valve, an outlet in the air supply piping, arranged behind the magnetically controlled valve, a throttle in the said outlet, an outlet valve provided with an exciting winding and disposed in the said outlet, a cut-out relay provided with an exciting winding and in series with the exciting winding of the outlet valve, and a second contact thermometer in the heated car, the operating temperature of the said second thermometer being below that of the thermometer connected in series with the exciting winding of the magnetically controlled valve, the second contact thermometer being connected in series with the exciting winding of the cut-out relay.

13. A device forautomatically regulating the supply of heating medium to the air heater of an air-heating plant in a railway car, comprising a valve in the piping which supplies heating medium to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, connected with the spring body, a vaporising liquid in the vaporising vessel, a jacket surrounding the vaporising vessel, a conduit branching off from the heating medium piping behind the valve for supplying a branch cur-, rent of heating medium to the jacket, a piping for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, means for automatically varying the cooling of the vaporising vessel by the air in dependence upon the temperature of the car, and an overpressure flap in the piping supplying heating medium to the air heater behind the branching point of the branch pipe supplying heating medium to the jacket.

14. A device for the automatic regulation of the supply of steam to an air heater provided with a condensate discharge in air-heating plant for a railway car, comprising a valve in the piping supplying steam to the air heater, a thermal relay for controlling the valve, said relay comprising in combination a spring body for actuating the valve, a vaporising vessel, combined with the spring body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of heat to the vaporising vessel, a jacket surrounding the vaporising vessel, a feed pipe for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, means for automatically varying the cooling of the vaporising vessel by the airin dependence upon the temperature of the car, a throttle in the condensate discharge pipe of the air heater, and a conduit branching of]? from the condensate discharge pipe before the throttle and extending to the jacket.

15. A device for the automatic regulation of the supply of steam to an air heater provided with a condensate discharge in air-heating plant for a railway car, comprising a valve in the piping supplying steam to the air heater, a

thermal relay for controlling the valve, said relay 1'' comprising in combination a spring body for actuating the valve, a vaporising vessel, combined with the spring body, a vaporising liquid in the vaporising vessel, means for supplying a constant quantity of heat to the vaporising vessel, a jacket surrounding the vaporising vessel, afeed pipe for supplying a branch current of the heating air to the jacket, a discharge pipe extending from the jacket into the atmosphere, means for 

